According to the conventional construction of an electronic timepiece using hands for indicating the time rather than a digital display, the battery for powering the timepiece must be located at one side of the shafts for the minute and hour hands which are centrally located. Hence, the diameter of the timepiece movement must be more than twice the diameter of the battery. The smallest battery presently available for use in timepieces is 7.9 mm in outer diameter. With conventional construction, the diameter of an electronic timepiece movement using such a battery is about 20 mm. If it is desired to make a smaller timepiece, the battery must protrude from the outer circumference of the timepiece movement. It is hence impossible to make a timepiece of small size even if the timepiece movement is small because the case must be made large enough to cover the protruding battery.
On the other hand, if a movement is made small sized, it is necessary to make it thicker in order to accommodate a battery inside the outer circumference of the movement. Hence the timepiece cannot be made thin. For example, if the timepiece movement is made approximately 15 mm in diameter it must be about 13 mm thick.